The overall objective of this research is to study the structure, metabolism and function of animal cell surfaces. This interest has been stimulated by recent evidence relating cell surfaces with regulations of cellular growth. It is the specific purpose of the present research project to understand the mechanism of density dependent synthesis of glycolipids in normal cells and to determine what factors alter this process when cells are transformed by tumorigenic viruses. We will attempt to distinguish between the effects due to growth rate and those due to culture density by comparing growing and non growing sparse cells with dense cells which are also either growing or not growing. The glycolipid changes will be localized within the cell. We will determine the generality of our observations by comparing them with normal and RSV-transformed chick cells.